From the Field: Kruger National Park

31 March 2020

Like much of the rest of the world, South Africa has closed down international travel and implemented measures that are aimed at minimizing the transmission of coronavirus. We are acutely aware that the situation can change on a daily basis. During a time of so much uncertainty, I count myself lucky to be out in the field where (quite literally) a breath of fresh air and wide-open spaces is for now the very best thing on offer.

Each year, we monitor Martial Eagle breeding performance at approximately twenty occupied nests in Kruger National Park. The long-term aim of this project is to understand what causes population declines and poor breeding in this species. Martial Eagles in Kruger lay a single egg starting in April, so right now we are busy putting up cameras in a selection of nests before incubation begins. Martial Eagles don’t breed every year, and here in Kruger some pairs make rather sporadic attempts, but we can already see if nests are likely to be used because the eagles have lined them with green leaves.

Kruger has changed a lot since my previous visit at the end of last year. There has been good rainfall, and the bush has come alive. We are wading through long grass to get to the nests. We are always accompanied by a South African National Parks game guard, and our senses are extra alert knowing that anything could be hidden in the next patch of thick vegetation. The grass is also infested with ticks — really tiny ones which manage to get everywhere before you even have a chance to notice. Their bites are itchy and last for days, but just a quick scroll through my news feed and I’m reminded that I’d rather this any day!

The breeding performance of Martial Eagles has been worryingly low every year since this research began in 2013. Although it is still very early to tell what will happen this year, my first impressions are good. Many nests have been lined, and so far we have installed eight nest cameras.

The eagles build large stick nests in trees like leadwoods, knobthorns and jackalberries. Each tree poses a different challenge for us to put up ropes and get the camera up there. Some nests are in dead trees or on inaccessible limbs which we can’t climb to. We check these nests with a camera attached to a telescopic pole to see what’s going on, but we don’t get the in-depth information that a nest camera can give. The nest cameras take time-lapse photos throughout the breeding season so we can see if nests are successful, what prey species are bought to the chick, and if they fail what the cause of failure is. Later in the year, we will be back in the field to change batteries and memory cards in the cameras. We are working with the FitzPatrick Institute of African Ornithology and the Endangered Wildlife Trust on this project. Ultimately this information will help us to understand what Africa’s largest eagles need to survive so that we can protect them better in the future.